A display panel generally has a large number of pixels arranged in a two dimensional array. To drive the display panel, an active matrix substrate includes a large number of switching elements made of thin-film transistors or TFTs to activate the pixels.
It is known in the art that each switching element has a drain electrode, a source electrode and a gate electrode and each pixel has a pixel electrode and a storage capacitor to store electric charges between the pixel electrode and a common line. As the size of the TFT-driven display panel becomes large and its resolution becomes high, the addressing time of the pixels becomes very short, the line resistance of the addressing lines becomes very high, and the capacitance loading of the display panel becomes high, causing the charging efficiency of the display pixel to decrease significantly. It is a recognized issue to lower the addressing line resistance and the capacitance loading, and to increase the TFT transconductance for the TFT array.